The fixing of such a board in an outer housing sets numerous problems, in particular when the electric circuit carried by the board operates in very high frequency ranges, for example from a few MHz to several GHz. This is the case in particular with some repeaters used on long-distance telephone connections which convey signals whose maximum frequency can reach a few tens of MHz and in which the electric operation of the amplifiers installed on one or several boards must be verified up to frequencies of the order of GHz.
One of the difficulties which arise in amplifiers of this type is the provision of equipotential connections; in particular the electric circuits of the amplifiers installed on the boards include a number of points which must be brought to a common reference potential identical to the potential of the metallic frame on which the boards are installed. In the following part of the specification, the assembly of these equipotential connections will be called "electrical earth".
A simple solution for forming these equipotential junctions as exactly as possible consists in metal-coating the periphery of the board and in soldering this metal coated part to the frame, but it is necessary to take into account the various temperature variations to which the board and frame assembly will be subjected during operation, essentially due to the thermal dissipation of the electrical components and to variations in ambient temperature. These variations in temperature result in different dimensional variations for the board which will, for example, be made of ceramics and for the frame which will be metal. It is therefore necessary for the mechanical connection between the board and the frame to compensate for these dimensional variations as well as for the production tolerances of the parts constituting the assembly.
Preferred embodiments of the present invention provide a connection between a support board of an electric circuit and a surrounding frame meeting these requirements.